(A) Field of the Invention
The present invention is related to a built-in self-test (BIST) apparatus and a BIST method, and more particularly to a BIST apparatus and a BIST method applied to a digital-to-analog converter (DAC).
(B) Description of the Related Art
Given the advancement of integrated circuits with high integration, more and more circuits are being integrated into a system-on-a-chip, SoC. Plenty of DACs, analog-to-digital converters (ADCs) and mixed-signal circuits with a combination of analog functions and digital functions are applied to fields like wireless communications, data conversion system, satellite communications, etc. Recent years see the development of BIST technology intended for the aforesaid circuits, wherein self-tests are directly conducted on hardware by built-in circuits in order to cut cost and shorten test duration.
The digital-to-analog (DA) voltage signals have been directly processed in the BIST for a DAC for years. However, it is difficult to distinguish analog signals from noise. Hence, despite their unsatisfactory benefit, additional auxiliary circuits or special methods have usually been used to facilitate the aforesaid data processing. Furthermore, the completion of the aforesaid data processing is a demanding job, for the reasons that, to process high-speed DA signals, not only an additional circuit for measuring voltage is needed, but also the sampling frequency of the DA signals should be more than two times the frequency of the DA signals themselves.